Every Rock Has A Story:

Every Rock Has A Story - Copper

This is a vein of pure copper that precipitated from a hot water (hydrothermal) solution that was driven into a fracture in the 1.1 billion year old Nonesuch Shale Formation, at the White Pine mine in the Keweenaw area of the Upper Peninsula, near the Porcupine Mts. The deep copper-bearing hydrothermal fluids were injected along fractures and faults during regional compression of the great mid-continent rift, caused by the collision of a continent along the eastern margin of proto-North America roughly 1 billion years ago.